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Abstract:

The method of transmitting data in real time with low power via a wireless
line in which channel status is searched to prevent data loss by
transmitting and receiving retransmission a packet every time when there
is an interference, and to minimize power consumption necessary for
transmission and reception by transmitting and receiving the
retransmission packet at a specific period when there is no interference.
The method includes: transmitting real time packet data containing reply
requesting information from a master to a slave; determining channel
status by analyzing whether the master receives the reply packet and
reply information; and adjusting the number of times of requesting the
reply packet by selectively recording the reply requesting information
contained in a control information field of the real time packet data
according to the determined channel status. Power consumption due to the
transmission and reception of the reply packet can then be reduced.

Claims:

1. A low power wireless real time data transmitting method in a wireless
real time data transmitting apparatus comprising a master to transmit
real time data via a wireless line and a slave to receive the real time
data transmitted from the master, the method comprising:transmitting real
time packet data containing reply requesting information from the master
to the slave;determining a channel status by analyzing whether the master
receives the reply packet and reply information; andadjusting the number
of times of requesting the reply packet by selectively recording the
reply requesting information contained in a control information field of
the real time packet data according to the determined channel status.

2. The low power wireless real time data transmitting method according to
claim 1, wherein the determination of the channel status is carried out
by which the control information contained in the reply packet
transmitted from the slave is analyzed, it is determined that there is no
channel interference when there is no retransmission request, and the
channel interference is determined when the retransmission request
information exists in the control information or the reception of the
reply packet is failed.

3. The low power wireless real time data transmitting method according
claim 1, wherein the number of requesting the reply packet is adjusted in
response to a predetermined specific period in order to reduce a power
consumption when there is no channel interference as a result of the
determination of the channel status.

4. The low power wireless real time data transmitting method according to
claim 1, wherein the number of times of requesting the reply packet is
adjusted whenever transmitting the packet when there is the channel
interference as a result of the determination of the channel status.

5. The low power wireless real time data transmitting method according to
claim 3, wherein the number of times of requesting the reply packet is
adjusted whenever transmitting the packet when there is the channel
interference as a result of the determination of the channel status.

Description:

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to a method of transmitting data in
real time with a low power via wireless line, and more particularly, to a
method of transmitting data in real time with a low power via a wireless
line in which a channel status is searched to prevent data loss by
transmitting and receiving a retransmission packet every time when there
is an interference, and to minimize a power consumption necessary for
transmission and reception by transmitting and receiving the
retransmission packet at a specific period when there is no interference.

[0003]2. Description of the Related Art

[0004]Generally, since, in a wireless real time data transmission system,
transmission and reception of data are carried out via a wireless link,
transmitted data may be lost or damaged. When there is data loss or data
damage, data that is not serviced in real time should be retransmitted.
In other words, in a case of a typical real time service such as a voice
service, it is not necessary to retransmit vocal data even when the vocal
data is lost or damaged. However, in a packet data service, when data is
lost or damaged, a correct message is transmitted only by retransmitting
the data. Thus, in a communication system in which the data transmission
is carried out, data is transmitted by one of various methods of
retransmitting data.

[0005]In the conventional wireless real time data transmitting system, a
method of transmitting data in real time via a wireless line is carried
out by which a data transmission terminal transmits control information
containing information requiring a reply packet thereon whenever
transmitting every packet, and a data receiving terminal, in order to
prevent the data loss when there is a channel interference, transmits the
reply packet containing the control information required in the
retransmission to the data transmission terminal whenever receiving the
packet data.

[0006]In the channel interference, a rapid data recovery can be carried
out by replying of the retransmission control information every time.
However, the retransmission control information exists as overhead
information in the status that there is no channel interference.

[0007]As described above, in the conventional wireless real time data
transmission system, since the control information necessary for the
retransmission is always transmitted to the data receiving unit every
time regardless of the channel status and the data receiving unit loads
the control information necessary for the retransmission on the reply
packet every time and transmits the reply packet to the data transmitting
unit, power consumption is increased.

SUMMARY OF THE INVENTION

[0008]Therefore, the present invention has been made in view of the above
problems such as power waste generated by transmitting and receiving the
reply packet in the conventional wireless real time data transmitting
system, and it is an object of the present invention to provide a low
power wireless real time data transmitting method of properly controlling
times of transmitting and receiving a reply packet according to whether
there is an interference by searching channel status so as to solve the
power waste generated by the transmission and reception of the reply
packet.

[0009]It is another object of the present invention to provide a low power
real time data transmitting method of transmitting and receiving a reply
packet every time when there is an interference by searching channel
status so as to prevent data loss, and of transmitting and receiving the
reply packet at a specific period when there is no interference so that
power consumption necessary for the transmission and reception can be
minimized.

[0010]In the low power wireless real time data transmitting method
according to the present invention, a device to transmit data is regarded
as a master, and a device to receive transmitted data and to transmit a
reply packet is defined as a slave.

[0011]In accordance with an aspect of the present invention, the above and
other objects can be accomplished by the provision of a low power
wireless real time data transmitting method in a wireless real time data
transmitting apparatus including a master to transmit real time data via
a wireless line and a slave to receive the real time data transmitted
from the master. The method includes: transmitting real time packet data
containing reply requesting information from the master to the slave;
determining a channel status by analyzing whether the master receives the
reply packet and reply information; and adjusting the number of times of
requesting the reply packet by selectively recording the reply requesting
information contained in a control information field of the real time
packet data according to the determined channel status.

[0012]The determination of the channel status is carried out by which the
control information contained in the reply packet transmitted from the
slave is analyzed, it is determined that there is no channel interference
when there is no retransmission request, and the channel interference is
determined when the retransmission request information exists in the
control information or the reception of the reply packet is failed.

[0013]Moreover, the number of requesting the reply packet is adjusted in
response to a predetermined specific period in order to reduce a power
consumption when there is no channel interference as a result of the
determination of the channel status.

[0014]Moreover, the number of times of requesting the reply packet is
adjusted whenever transmitting the packet when there is the channel
interference as a result of the determination of the channel status.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a block diagram illustrating a wireless real time data
transmitting apparatus employing a low power wireless real time data
transmitting method according to the present invention;

[0016]FIG. 2 is a block diagram illustrating frame structures of a data
packet and a reply packet that are transmitted in the present invention;

[0017]FIG. 3 is a flowchart illustrating the low power wireless real time
data transmitting method according to the present invention;

[0018]FIG. 4 is a view illustrating a status of the packet when there is a
request for the retransmission of a previous transmittal packet from a
slave in the present invention; and

[0019]FIG. 5 is a view illustrating a status of the packet when a master
device fails the periodical reception of the reply packet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020]Hereinafter, the preferred embodiments of the present invention will
be described in detail with reference to the accompanying drawings.

[0021]FIG. 1 is a block diagram illustrating a wireless real time data
transmitting apparatus employing a low power wireless real time data
transmitting method according to the present invention.

[0022]Here, a reference numeral 110 is assigned to a data transmitting
unit to carry out a real time data transmission, to request a reply
packet through a control information field of a transmittal packet when
there is a request for a reply packet, to request the reply packet at a
specific period when there is no channel interference by analyzing reply
information, and to request the reply packet every time every there is
packet transmission when there is a channel interference. A reference
numeral 120 is assigned to an RF interface connected to the data
transmitting unit 110 to modulate the transmitting data outputted from
the data transmitting unit 110 into an RF signal and to transmit the RF
signal, and to receive and demodulate a reply packet signal transmitted
from the exterior to deliver the data transmitting unit 110.

[0023]Moreover, a reference numeral 210 is assigned to an RF interface to
receive a wireless signal transmitted from the RF interface 120 and to
demodulate the received wireless signal into an original signal, and to
modulate the transmitted reply packet data into an RF signal. A reference
numeral 220 is assigned to a data receiving unit to carry out error
correction of data received from the RF interface 210, to analyze the
control information recorded in the control information field of the
packet, to generate a reply packet when there is a request of a reply
packet, and to deliver the reply packet to the RF interface 210.

[0024]The data transmitting unit 110 includes a transmitting buffer 111 to
temporally store real time transmitting data, and a transmitting buffer
controller 112 to control data storing of the transmitting buffer 11, a
parity generation for the generating of control information, an error
restoration, and a detection of the transmitting data, and to determine
whether the transmitting data should be retransmitted and new data should
be transmitted according to the control information analyzed from the
received reply packet. Moreover, the data transmitting unit 110 includes
a data analyzing unit 113 to generate a parity for the error correction
and detection of the transmitting data in response to the control of the
transmitting buffer controller 112, to analyze the control information of
the received reply packet, and to deliver a result signal of the analysis
as a signal used to determine whether the transmitting data should be
retransmitted to the transmitting buffer controller 112. Here, the data
analyzing unit 113 preferably includes a parity generator 113a to
generate the parity and a reply information error detecting and restoring
device 113b to detect and restore an error of the reply information. The
data transmitting unit 110 includes a transmitting/receiving controller
114 in association with the transmitting buffer controller 112 to
generate a packet for the transmission of the transmitting data and to
receive the reply packet to deliver the reply packet to the data
analyzing device 113.

[0025]Moreover, the data receiving unit 220 includes a
transmitting/receiving controller 221 to receive the wireless real time
data transmitted from the data transmitting unit 110 and to transmit the
reply packet, and an error correcting and parity generating unit 222 to
extract a parity from the real time data, to detect and correct an error
of the received data according to the extracted parity, and to generate a
parity for the transmission of the reply packet. Here, the error
correcting and parity generating unit 222 preferably includes an error
detecting and restorer 222a to detect and correct the error of the
received data and a reply information parity generator 222b to generate
parity for the transmission of the reply packet. Moreover, the error
correcting and parity generating unit 222 includes a receiving buffer 223
to temporally store the received data, and a receiving buffer controller
224 to control the receiving buffer to store data, to control the
generating of control information of the reply packet and the parity
generation for the error correction and detection, and to determine
whether the reply packet would be transmitted according to the control
information analyzed from the received packet.

[0026]Operation of the low power wireless real time data transmitting
method, employed in the wireless real time data transmitting apparatus,
will be described in detail with reference to FIG. 2 as follows.

[0027]The transmitting buffer controller 112 of the data transmitting unit
110 requests a reply packet to the transmitting/receiving controller 114
to generate control information such that the master determines whether
there is channel interference. By doing so, the transmitting/receiving
controller 114 generates a data packet containing transmitting data and a
parity that pass through and are transmitted through the transmitting
buffer 111 and the data analyzing unit 113 sequentially and the reply
packet request information requested by the transmitting buffer
controller 112. In other words, like the structure of the data packet
illustrated in FIG. 2, the transmitting data to be transmitted is
recorded in a real data field, data information to indicate what is the
parity information and the transmitting data and reply information to
indicate whether there is a reply packet request in the control
information field, device synchronizing information in a synchronizing
field to generate a data packet, and delivery of the data packet to the
RF interface 120. Then, the RF interface 120 converts the data packet
into an RF signal and transmits the RF signal to the slave.

[0028]The RF interface 210 of the slave receives the data packet
transmitted from the master to demodulate the same. A path of the
demodulated data is controlled by the transmitting/receiving controller
221 of the data receiving unit 220 and the error correction and analysis
of the control information of the received data are carried out by the
error correcting and parity generating unit 222. The path of the data is
controlled by the transmitting/receiving controller 221 of the data
receiving unit 220 and the error correction and analysis of the control
information of the received data are carried out by the error correcting
and parity generating unit 222. The received data in which the error
correction has been carried out is stored in the receiving buffer 223 and
is outputted to a device to need the received data, and the analyzed
control information is delivered to the receiving buffer controller 224.
The receiving buffer controller 224 analyzes the delivered control
information to deliver a signal of generating a reply packet to the
transmitting/receiving controller 221 and to command the error correcting
and parity generating unit 222 to generate parity for the reply packer
transmission when there is a reply packet request. By doing so, the reply
information parity generator 222b of the error correcting and parity
generating unit 222 generates the parity for the reply packet
transmission and delivers the same to the transmitting/receiving
controller 221. The transmitting/receiving controller 221 received the
parity for the reply packet transmission records information containing
information about the parity for the reply packet transmission and
information about the received packet in the control information field,
records synchronizing information of indicating device information in a
synchronizing code field to generate the reply packet like the structure
of the reply packet as illustrated in FIG. 2, and the RF interface 210
modulates the reply packet into the RF signal and transmits the same to
the master.

[0029]The RF interface 120 of the master receives the reply packet
transmitted from the slave to demodulate the same, and the
transmitting/receiving controller 114 delivers the demodulated receiving
packet to the data analyzing unit 113. The reply information error
detecting and restoring device 113b of the data analyzing unit 113
extracts the control information of the demodulated receiving packet and
analyzes information such as reception used to determine whether there is
a channel interference contained in the control information and delivers
the same to the transmitting buffer controller 112.

[0030]Then, the transmitting buffer controller 112 determines whether
there is the channel interference according to the analyzed control
information. Here, the transmitting buffer controller 112 determines that
there is the channel interference when the reply packet is not received
within a predetermined time period after transmitting the packet
containing information of requesting the reply packet.

[0031]As a result of the determining whether there is the channel
interference, if there is no channel interference, the transmitting
buffer controller 112 regards that the retransmission is not required and
controls to request the reply packet according to a specific period (this
means a period in which a packet requesting period is long). Moreover, if
there is the channel interference, the transmitting buffer controller 112
controls to contain and transmit the information of requesting the reply
packet in the control information whenever transmitting the packet.

[0032]In other words, if the channel interference does not exist, the
reply packet is not requested whenever transmitting the packet, but at a
predetermined time interval (for example, after transmitting several
packets). By doing so, since it is not necessary to transmit the reply
packet every time when there is no channel interference, the power
consumption, required to transmit the reply packet every time, can be
reduced.

[0033]FIG. 3 is a flowchart illustrating the low power wireless real time
data transmitting method according to the present invention. In FIG. 3, a
reference numeral S indicates processing steps.

[0034]As illustrated in FIG. 3, the low power wireless real time data
transmitting method according to the present invention includes
transmitting S101 real time packet data containing reply requesting
information from a master to a slave, determining S103 and S105 channel
status by analyzing whether the reply packet is received and reply
information by the master, and adjusting S107, S109, and S111 the number
of times of requesting the reply packet by selectively recording the
reply requesting information contained in the control information field
of the real time packet data.

[0035]Operation of the low power wireless real time data transmitting
method according to the present invention will be described in detail
with reference to FIGS. 4 and 5 as follows.

[0036]Firstly, in the step S101, the transmitting/receiving controller 114
of the master generates the real time packet data containing the reply
requesting information of determining whether there is the channel
interference and transmits the same to the slave.

[0037]In the step S103, the reply information transmitted from the slave
is received, and the reply information is analyzed and whether the reply
packet is received is checked to determine the channel status in the step
S103. In other words, the control information contained in the reply
packet transmitted from the slave is analyzed. It is determined that
there is no channel interference when there is no retransmission request
and it is determined that there is channel interference when the
retransmission request is in the control information or the reception of
the reply packet is failed.

[0038]If it is determined that there is channel interference, like the
step S105, information of requesting the reply packet is loaded on the
control information whenever transmitting the packet and the packet is
transmitted. Thus, if there is channel interference, the slave should
generate the reply packet and transmit the same to the master whenever
receiving the packet.

[0039]On the other hand, if there is no channel interference, like the
steps S109 and S111, the number of times of the requesting the reply
packet is adjusted in response to the predetermined specific period in
order to reduce the power consumption.

[0040]In other words, if there is no channel interference, the reply
packet is not requested whenever transmitting the packet, but at a
predetermined time interval (for example, after transmitting several
packets). By doing so, since is not necessary to transmit the reply
packet every time when there is no channel interference in the slave, the
power consumption required to transmit the reply packet every time can be
reduced.

[0041]FIG. 4 is a view illustrating a status of the packet when there is a
request for the retransmission of a previous transmittal packet from a
slave in the present invention, and FIG. 5 is a view illustrating a
status of the packet when a master device fails the periodical reception
of the reply packet. Here, a packet indicated by "R" represents a packet,
to be transmitted, on which the reply request is loaded. As illustrated
in FIG. 5, when the master fails to receive the reply packet
periodically, the retransmission request is transmitted until data can be
substantially loaded at a data transmission rate.

[0042]As described above, in the present invention, the power consumption
can be reduced by reducing the transmission and reception of a specific
packet (for example, the reply packet). A rate of the power consumption
required for the transmission and reception reduced according to the
reply requesting period can be expressed by a formula as follows.

Power consumption saving rate (%)=(period-1)/(overall length of a
packet*period)*100

[0043]In other words, if assuming that the length of the reply packet is
1/3 of the length of the data packet, since the length of the data packet
is 3 when the length of the reply packet is 1 (one), the overall length
of the packet is set to 4, and, if the reply requesting period is set to
2, the power consumption required for the transmission and reception can
be reduced by 12.5%. Moreover, the power consumption can be reduced by
16.7% when the reply requesting period is set to 3, and by 18.75% when
the reply requesting period is set to 4. As such, although the power
consumption can be reduced by 25% as much as possible by increasing the
reply requesting period, since a buffer prepared for the retransmission
request is increased as much

[0044]as the reply requesting period is increased, it is preferred to
obtain and employ an optimal value according to an applied system.

[0045]As described above, although the present invention is described by
an embodiment in which the master transmits the control information and
the real time data and the slave transmits simple control information,
the present invention is not limited to this.

[0046]For example, it is possible that a system in which the master
transmits the simple control information and the slave transmits a great
deal of data can be applied to a system in which the transmission of the
master is controlled by the control information of the slave through a
simple modification. In another case, the power consumption can be more
reduced than that proposed in the embodiment of the present invention by
which both of the master and the slave transmit the control information
to control the transmission of the other party.

[0047]As described above, according to the present invention, the channel
status is searched and the number of times of transmission and reception
of the reply packet is properly controlled according to whether there is
the channel interference, so that the power waste generated by the
transmission and reception of the reply packet can be solved.

[0048]Moreover, when the channel status is searched and there is the
channel interference, the transmission and reception of the
retransmitting reply packet is carried out every time to prevent the data
from being lost, and the power consumption required for the transmission
and reception can be minimized by transmitting and receiving the
retransmitting reply packet at a specific period when there is no channel
interference.

[0049]Although the preferred embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the invention as
disclosed in the accompanying claims.